In the manufacture of corrugated paperboard containers, sheets of paperboard are conveyed through a press such as a printer slotter wherein one surface of the sheets is printed. Also, the sheets are creased and slotted to thereby produce a printed box blank.
In a conventional printer slotter, there is an ink fountain. The fountain is generally defined by two cooperating fountain rollers and a printing plate roller. In some printer slotters, the fountain is defined by only one fountain roller with a cooperating doctor blade. Sheets of paperboard fed into the printer slotter are contacted by the printing plate roller. Printing ink is delivered from a supply source to the trough formed by the juxtaposed fountain rollers. One fountain roller is usually provided with a resilient covering which bears against the ectched or engraved surface of the other fountain roller. A small amount of ink is retained by said surface and then applied to the printing plate roller.
When it is desired to change from one color ink to another, the fountain rollers and the ink circulation system must be completely clean. The cleaning procedure takes substantial time. After the ink present in the trough has been allowed to drain back to the supply container, a wash liquid such as water is circulated through the system until the water runs clear. The time spent in cleaning the system is nonproductive time and therefore there has been a long-felt need for a system to reduce the wash-up time between color changes. The present invention materially reduces the wash-up time.
This invention relates to a dual ink circulation and wash-up system for a press such as a flexographic press for printing sheets of corrugated paperboard. The press supports a printing medium application means. A plurality of printing medium supply means are provided for sequentially supplying the printing medium to said application means.
The system of the present invention includes at least one receptacle positioned adjacent said application means to receive any excess printing medium therefrom. The receptacle has at least two compartments, with each compartment having a drain conduit. Conduit means are provided for connecting each compartment with a wash liquid supply means for selectively introducing a wash liquid thereinto. A means is provided to selectively divert liquid from the application means into one of said compartments.
It is an object of this invention to provide apparatus and/or method to reduce the time required to clean a printing press between color changes.
It is another object of the present invention to provide a novel system which simultaneously facilitates washing part of the system while printing sheets with another part of the system.
It is another object of the present invention to provide a press such as a printer slotter having two ink distribution systems connected to a single ink fountain.
Other objects will appear hereinafter.